Since installing avast! 5.0, my system has been slowed down, as far as browsing with Windows Explorer is concerned. I have enabled all of the SCAN NOW options to "Speed up scanning by using the persistent cache", however, using Windows Explorer is still significantly slower than it was using avast! 4.8.

Surprisingly, playing games and using Mozilla Firefox 3.5 are not slowed down hardly at all. It's browsing Windows Explorer which is making the process "AvastSvc.exe" take up 80%+ of my C.P.U. (Windows Task Manager shows me this.), thus making Windows Explorer sometimes load painfully slow.

I am running an ASUS computer model, using Microsoft Windows Vista Home Premium 32-bit, with 3 GigaBytes of R.A.M..

This is frustrating me because I know avast! 5.0 is really awesome, but these speed issues need to be addressed. From what I've seen on the avast! forum, I am not alone with avast! 5.0 performance issues.

Any help resolving this speed problem would be very much appreciated. Thanks in advance.

Sorry, but I don't feel like testing each and every shield one by one. At least, not right now.

All I know is that it is "AvastSvc.exe" causing the issue with immense C.P.U. usage. "AvastUI.exe" is taking little to no C.P.U. usage at all.

@ scythe944:

I first installed avast! 5.0 Pro over avast! 4.8 Professional Edition. (avast! 4.8 had an activated license, by the way.) The install of 5.0 went through without a single issue, so it seemed. (After installation I did not restart my computer, as I was not prompted to do so by avast!.) However, avast! 5.0 Pro itself, after installation, caused all sorts of problems. I had to use Revo Uninstaller's Advanced uninstall mode to remove both avast! 4.8 Professional Edition (Yep, avast! 5.0 Pro's install process did not remove any avast! 4.8 Professional Edition files.) and avast! 5.0 Pro, including their registry keys and left over files. Afterwards, I restarted the operating system. I'd also like to add here that transferring the existing 4.8 avast! license over to 5.0 was not as easy as insinuated on this page. The "Your current remaining license period will be maintained. Simply download and install the new version." text on that page is blatantly not true. Rather, a manual copy of the current 4.8 license was actually needed, which I simply could not get to copy over to, nor work, in 5.0.

After restarting, I double checked that the Program Files folder didn't contain any avast! files, and sure enough, all that was left was an empty Alwil Software folder. Being a more than satisfied avast! 4.8 user for at least 2 years, I decided not to leave Alwil Software as I was previously a very happy user. I thought: 'Okay, so the avast! 5.0 Pro upgrade did not go well at all, but perhaps the free version will work. Why not give it a go?' So, I proceeded to download it. It installed successfully without any problems. This time, I restarted my operating system. Everything was running smoothly, finally.

Until now, that is. I don't know why, but browsing Windows Explorer is very slow. Mozilla Firefox 3.5 is now also going into Not Responding mode three times more often than it ever used to. In addition to this, when I played Grand Theft Auto IV today, launching the game was painfully slower. All of these slow downs, lags, and performance issues were not present at all in avast! 4.8. Period.

As far as conflicts are concerned, I really don't think this is a potential cause. I use only Windows Firewall, which has avast! 5.0 Free Antivirus permitted to fully access the internet. Windows Defender is fully disabled also. There is no other security software on my system, other than Blue Coat K9 Web Protection, a website filtering application, which never conflicted with avast! 4.8. Ever.

avast! 5.0 Free Antivirus is not reporting any issues or problems in its interface.

If you require any more details/information, I'd be quite happy to assist.

Oh, and one more thing. Here's a screenshot of avast! 5.0 Free Antivirus taking up the majority of the C.P.U. when trying to browse my Documents folder.

Using avast! 5.0 Free Antivirus was the first time in a long time I've ever seen Windows Explorer's green loading bar show up on such a regular basis.

I don't think I have seen 5 do that but 4 on a bad download will jack CPU to 100% no matter what your using. You need to uninstall and reinstall. And the older guys like DavidR would tell you to clean after the uninstall with the cleaning tool. Then reload. Somehow you got a bad download of 5.0

I thought this had been fixed, but today it has started using too much of my C.P.U. again.

Looks like either:

A - the repair didn't work properly,

or

B - the repair worked, but the latest avast! 5 program update has badly intercepted the previous repair.

Just so you know, it's doing it exactly as before. AvastSvc.exe is the one taking up the C.P.U. and it's doing so in the same fashion as it was before I THOUGHT I fixed it vai avast!'s "Repair" function. Something's gone wrong again!

For details on my computer's spec's and details on the avast! C.P.U. problem, please refer to my first posts in this thread.

Do you have latest version 5.0.418? or wich one? because maybe latest version have those bugs fixed. Why dont u try a registry cleaner like: comodo system cleaner, or CCleaner? Maybe cleaning your system helps avast 5 performance issues. Maybe something is wrong with your windows.